I’m skipping my workout today. My back is hurting with sciatic pain shooting down the backs of my legs. It’s not super-bad, but enough to make me pause. I’ll rest today and see how it feels tomorrow.
A bad back, exacerbated by morbid obesity, requires additional consideration when exercising. I’d rather miss a day or two than re-injure my back and be out of action for weeks or worse.
Update: Thanks for the ice packs, Joe. 
For the morbidly obese, traditional exercise presents serious problems. Co-morbidities like hip and knee joint problems, back trauma, cardiac and respiratory disease, and other complications makes exercise difficult and dangerous. Before engaging in any exercise program, consult your doctor and follow his or her instructions. If you have the resources, you should work with a physical rehabilitation professional who has expertise in working with the morbidly obese.
When I began my weight loss journey, I did not exercise beyond walking around a bit. I had some cardiac problems and was very short of breath, but as the weight dropped away, I was able to do more.
Consistency is the key. Here are the things I’ve found works for me:
Since I have a bad back, except for dumbbells, I stay away from free weights. A nautilus machine can work, but if I’m not careful, I screw up my back which destroys my momentum until I heal. That’s one reason I sold my BowFlex.
Keep it simple. Stay consistent.
Above all, consult with your doctor before embarking on any exercise or diet program if you don’t want to drop dead of a heart attack and be buried in a piano-sized shipping crate.